The NBA game time uses an A.C. motor to move the hoop left and right. The motor arm rests between 2 Delrin block that ride on an HPDE channel. The backboard motor will always attempt to keep itself centered, it accomplishes this by using an optical sensor to read reflective tape on the back of the motor arm determine its position. If the display board does not see the reflection from the tape it will try to move the motor to search for the signal periodically throughout the game. To accomplish motor movement the display board sends a low voltage signal to a sold state relay that controls the incoming A.C. voltage to the motor, when the signal is present the relay connects the internal contacts completing the circuit causing the motor to move.
WARNING—when servicing the backboard assembly keep your fingers clear of the motor arm to
Troubleshooting the back board not moving
Step 1 - Check that the movement is enabled in programming
Step 2 - Check the set screw in the motor arm is tight
Step 3 - Check for incoming AC voltage between tab 1+2 (brown wires) of the solid state relay
-if there is voltage then proceed to the next step
-If there is no voltage then inspect the harnessing and connections
Step 4 - check for the signal to turn the relay on. There is an indicator LED on the solid state relay which lights when the signal is present, you can also measure this signal using a multi meter between pins 3 (orange/blue trace wire) and 4 (violet wire) you will see 0vdc going to 12vdc when the signal is present. There will always be a constant 12vdc on tab 3 of the relay when using a digital ground for reference (J2 pin 2 on the display board) if the 12vdc is not present then check the voltage at the J6 pin 1 on the back display board.
- if there is a signal to the relay and the voltage to the motor is present then replace the motor
- if there is not signal to the relay then look for the signal coming from the J6 connector between pins 5 and 1. If there is a signal then check / repair the harnessing, if there is no signal the replace the display board
Back Board not centering
The optical encoder mounted on the rear of the back board assembly reads the reflective tape on the back of the motor arm to determine the home position of the motor. The back board will always try to move to the center position even if the movement is shut off in the programming.
Step 1 - inspect the optic sensor for signs of physical damage and that the reflective tape on the motor arm is still pre sent and not marred
Step 2 - check for power at the optic board between pins 1 (+12vdc , orange wire) and pin 3 (ground, black wire).
- if you have voltage then proceed to the next step
- if you have no voltage the inspect the wiring and connections back to the J6 connector on the timer board. If the wiring and connections are good and the display it lit the replace the display
Step 3 - look for the optics signal line between pins 2 (signal , white wire) and 3 (ground , black wire). You will see +5vdc when the reflector is in front of the optic and 0vdc when it is not reflecting.
-inspect the harnessing and connections to the display board at connector J6, unplug the connector and take a reading between pins 3 and 4, if the voltage is 3.3vdc the replace the sensor if not then replace the display board.